The NICHD's Contraceptive Clinical Trials network conducts Phase I, II and III clinical trials of a wide variety of new female and male contraceptive methods. The objective of this contract is for CCTN contractors to conduct female contraceptive clinical trials, conduct treatment trials of gynecologic conditions, and to develop research protocols on a task Order basis under an Indefinite Delivery/Indefinite Quantity (IDIQ) contract. There is a demand for estrogen-free contraception in order to reduce the risk of venous thromboembolism (VTE), particularly of obese women. A new long acting formulation of Levonorgestrel Butanoate (LB), delivered by injection, has been developed. Levonorgestrel (LNG) has a long history of clinical use in a variety of contraceptives (pills, intrauterine devices, and implants) and its efficacy and safety are well recognized. The CCTN will conduct a dose finding study of LB with doses selected on the basis of the results from the PK study which is being conducted under a task order at Oregon Health and Science University.